1. Field of the Invention
The present invention relates to the field of portable devices such as personal digital assistants or palmtop computer systems. More specifically, embodiments of the present invention relate to the recognition and correction of displayed text.
2. Related Art
As the components required to build a computer system have reduced in size, new categories of electronic devices and computer systems have emerged. One of the new categories of computer systems is the xe2x80x9cpalmtopxe2x80x9d computer system. A palmtop computer system is a computer that is small enough to be held in the hand of a user and can therefore be xe2x80x9cpalm-sized.xe2x80x9d Most palmtop computer systems are used to implement various Personal Information Management (PIM) applications such as an address book, a daily organizer (calendar, date book, etc.) and electronic notepads, to name a few. Palmtop computers with PIM software have been known as Personal Digital Assistants (PDAs). Many PDAs have a small and flat display screen associated therewith.
User convenience and device value are very important factors for portable electronic devices. Typically, portable electronic devices are employed while the user is on the run, e.g., in business meetings, on business travel, personal travel, in a vehicle, on foot, etc. Because the user may be occupied or busy while using the portable electronic device, the number of user steps or user tasks required in order to access information from an electronic device (or to store information into the electronic device) is crucial for producing a commercially successful and useful product. That is, the more difficult it is to access data from an electronic device, the less likely the user will perform those tasks to obtain the information. Likewise, the easier information is to obtain, the more likely the portable electronic device will be used to obtain that information and the more likely the portable electronic device will become a part of the user""s everyday activities.
Similarly, the more difficult it is to enter data into an electronic device, the less likely the user will perform those tasks required to communicate information. The easier it is to input information, the more likely the portable electronic device will be used to communicate that information and the more likely the portable electronic device will become a part of the user""s everyday activities. A stylus is frequently utilized in an on-screen handwriting system to enter data into a PDA. An important aspect of this operation is the ease with which the user can alter or correct such written information. The current state of the art is to move a visual selection tool or cursor around the screen and edit via the same mechanism that was used to enter the original text or data, however, extra strokes or entry actions are required to perform character deletions, etc.
The ability to modify information displayed on a touch-sensitive display screen, such as spelling errors or perhaps inaccurate numerical data, is an important function. Since the characters used to display information on the screen are relatively small, the spacing between characters is also quite small. This adds to the difficulty of locating, identifying and correcting a single character or groups of characters displayed on a display screen. One conventional method for allowing a user to correct mistakes requires that entire words be corrected at once. In effect, the user is required to identify a larger segment of information (for example a complete word) that is then displayed in magnified form for correction on the screen. However, there are many instances were only one character may be mistaken in a large word. It is very inconvenient to require a user to re-enter an entire word if just one character is mistaken.
Other correction techniques require that the user position a visual correction tool, e.g., a cursor, near the character to be corrected. The difficulty with the conventional correction methods involves the amount of time and effort required. For instance, to correct one mistake may require three to four separate actions, often in three disparate areas of the screen or device. For example, the user needs to position the cursor, perform a delete, reenter the new character, and then reposition at a last location. Therefore, existing systems and methods for accomplishing text correction are generally multiple step operations, and they generally are limited to altering only one character at a time. What is needed is a mechanism and method for allowing a user to easily make corrections with respect to displayed text without requiring the number of steps required of the cursor approach described above.
Accordingly, what is needed is a more generally applicable method or system that provides for more user friendly on-screen alterations or corrections of displayed information. What is also needed is a method or system that will allow operation on one or more characters, as well as replacement of portions of displayed information, in terms of the location of the information on the display screen. In addition, what is needed is a method or system that will function properly in response to handwritten strokes made on a touch screen by a user. What is also needed is a method or system that simplifies the alteration or correction process by reducing the number of steps required in existing methods and systems.
Just as one would make a voice correction by back tracking and repeating some of the correct information to provide context for where to place a correction, embodiments of the present invention use location and repetition of context to allow in-place correction of text on-screen without changing the input state of the device by persistently moving the cursor or creating selections of text (both of which are error prone due to the accuracy of pen placements required).
This correction recognizer is capable of using any handwriting system the user employs. The user simply rewrites the text to be corrected at the approximate on-screen location where the correction should take place. A user may have to repeat one or more correct characters to make the correction unique. The system then compares the new handwriting against the existing text to locate a match between them for at least one or more characters.
Audible feedback may be incorporated so the user will know when this match is found. A heuristic of placing the new text at the location where the best match is found is used. For instance, if you write xe2x80x9cyour rightxe2x80x9d and you need to correct it to xe2x80x9cyou""re rightxe2x80x9d then writing (""re) may not be enough since there are two r""s near each other. Writing (""re) (with a space) would be enough, or (u""re) would work. This allows the user to naturally correct just as they are used to when spelling words or numbers out vocally. A cursor or other correction tool is not required to make the correction.
A system and method for changing data displayed on a touch-sensitive display screen are described. The ability to modify information displayed on a touch-sensitive display screen, such as spelling errors or perhaps inaccurate numerical data, is an important function. Existing systems and methods for accomplishing this function are generally multiple step operations, and they generally are limited to altering only one character at a time. The present system and method recognize handwritten strokes made with a stylus on the touch-sensitive display screen of a PDA or palmtop computer in order to alter or correct displayed data. The present system and method is equally applicable with a display system in which a cursor is used to write handwritten strokes.
In one mode of operation, associating the location of the handwritten strokes on the display screen with one or more of the displayed characters will result in replacement of those characters by the handwritten (correction) strokes. In a second mode of operation, matching at least one of the handwritten strokes with one character of the displayed data will result in replacement of one or more characters of the displayed data with the handwritten characters. With the present system and method, the number of steps required to alter displayed data is reduced to the number of handwritten strokes. A significant reduction in time and effort as well as a simplification in application is therefore offered.
In one embodiment of the present invention, a portion of text to be modified is displayed on a touch-sensitive display screen. The input cursor is located at the end of the field of text. A stylus is used to handwrite a substitute character on the touch-sensitive display screen as the replacement for an existing character in the displayed text. Locating a portion of the handwritten stroke near an existing character on the display screen causes the system to examine this existing text nearby to identify the character to be replaced. Once a match is found between the correction text and the existing text, the substitute character is then automatically inserted in place of the existing character. It is possible to input more than one handwritten stroke at a time, thus allowing for simultaneous replacement of multiple characters.
In a second embodiment of the present invention, a portion of text to be modified is displayed on a touch-sensitive display screen. The input cursor is located at the end of the field of text. A stylus is used to handwrite one or more substitute characters on the touch-sensitive display screen as the replacement for a portion of the displayed text. It is appreciated that the replacement characters may be written in electronic ink over the text that is to be corrected. Locating one handwritten character in the vicinity of a similar existing character on the display screen identifies the position at which the replacement characters are to be inserted. Upon finding a match between a replacement character and an existing character, the substitute characters are automatically inserted in place of the existing characters with the matching characters occupying a similar location. The present system thus allows for replacement of portions of text composed of multiple characters.